Piston pump



Feb. 27, 1962 R. LE BARON BOWEN, JR 3,022,742

PISTON PUMP Filed March 30, 1960 FIG.4 FIG-5 me. 6 H

INVENTOR. RICHARD LEBARON BOWEN,JR

ATTOR N EYS 3,022,742 PISTON PUMP Richard Le Baron Bowen, In, 35Fessenden Road, Barringten, RI. Filed Mar. 3t), 1960, Ser. No. 18,677 2Claims. ((31. 103-153) This invention relates to piston pumps, and moreparticularly to those of the metering type for handling fluids of aviscous nature, such as heavy oils, grease, slurries, pastes, plasticmaterial, and the like.

Previously piston pumps which have been used for metering purposes havebeen provided with a suction along the bore and a discharge at one endthereof. It will be apparent that upon discharge a force is beingexerted substantially longitudinally of the piston and material willtend to seep down alongside of the piston which no only makes the pistonhard to reciprocate but also wears the piston whereupon a seal isquickly lost.

It is therefore an object of the present invention to provide a pistonfor a pump which will overcome some of the aforementioned disadvantages.

A more specific object of the invention is to provide a piston for apump of general type mentioned wherein a recess is providedlongitudinally of the piston at one side thereof remote from the suctionopening so that a force will be exerted by the piston against thesuction opening.

Also it is an object of the present invention to provide a piston pumpwith a suction opening along the bore and a discharge opening also alongthe bore spaced circumferentially about the bore with the axes thereofin the same plane normal to the axis of the bore together with a pistonhaving a recess cut longitudinally therein adjacent the dischargeopening.

With these and other objects in view the invention consists of certainnovel features of construction as will be more fully described andparticularly pointed out in the appended claims.

Referring to the drawings wherein like reference characters refer tolike parts:

FIGURE 1 shows a top view partially in section of the preferredembodiment of the pump;

FIGURE 2 shows a side elevation of the pump of FIGURE 1;

FIGURE 3 shows a section of FIGURE 1 taken along lines 33;

FIGURE 4 shows a top view partly in section of an alternate constructionof the piston of FIGURE 1;

FIGURE 5 shows an end view of the piston of FIG- URE 4;

FIGURE 6 shows a top view partly in section of another alternate form ofthe piston of FIGURE 1;

FIGURE 7 shows an end view of the piston of FIG- URE 6;

FIGURE 8 shows a section taken in the same location as FIGURE 3 of analternate configuration of the pump body shown in FIGURE 1.

In FIGURE 1 there is shown a pump having a body, generally indicated byreference character 11, formed with a suction opening 12 and a dischargeopening 13. Surrounding the discharge opening 13 and fastened to thebody 11 is a housing 14 formed with a bore 15. Within this bore there isa ball check valve 16 and a spring 17, the spring urging the ball valve16 against a seat 18 formed by the end of the discharge opening 13.Valve 16 is guided by means of vanes 19 formed within the bore ofhousing 14. Pump body 11 is provided with a bore 20 in which is fitted apiston 21, having one end thereof fastened to connecting rod 22 which isin turn connected to crank arm 23 fixed to the end of power shaft 24turned by power means not shown, such as an electric States Fatent3,922,742 Patented Feb. 27, 1952 the cut-otf point 31 in the suctionopening. This structure forms a piston with a blunt end 32 that ispreferable to using an inclined face. For instance, if the end of thepiston comes to a sharp point, and if abrasive materials are handled,the leading edge wears very easily so that with time the rate ofdischarge will tend to decrease due to the wear. The present piston thusprovides the maximum resistance to wear in contact with the wall of thebore 20. It should be further noticed that the shape of the piston 21 issuch that the force exerted by the pressure of the fluid in forcing theend of the piston against the wall of the bore 20 surrounding thesuction opening can be controlled, as shown in FIGURE 3. The forceexerted is a function of the width P of the recess 30. As this width Pis decreased the force is likewise decreased. FIGURE 3 also shows thatwe can control the length of this radial seal around the suction openingas indicated by angle A between the suction and discharge opening byvarying the width P of the recess 30. As angle A increases the length ofthe seal increases and becomes A/X1rd, where d=diameter of piston.

FIGURE 4 shows an alternate arrangement of a piston for FIGURE 1. Herethe width P of the recess in piston 41) has been decreased so that it isthe same as the width 36 of the discharge Opening 13 at the bore 20 inFIGURE 3. However, in order to give the fluid a maximum area between thepiston 40 and bore 20 to flow out through the discharge, slot 41 hasbeen cut into piston 40. FIG- URE 6 shows still another alternativearrangement of a piston for FIGURE 1. Piston 42 now has the Width P ofthe recess reduced to a very minimum, but to give the material area inwhich to flow, a counterbore 43 has been provided in piston 42, andfluid flows through slot 44 cut through the Wall of the piston. It isevident that piston 42 provides the maximum circumferential length ofsealing on both top and bottom between suction 12 and discharge opening13, since the angle A in FIGURE 3 is at a maximum. Further, the forceexerted on piston 42 tending to push it against the wall of bore 20 willbe reduced in proportion to the width P of slot 44 if the width 36 ofdischarge opening 13 in FIGURE 3 is likewise reduced to the samedimension.

FIGURE 8 shows an alternate arrangement utilizing the principles of theinvention where the suction and discharge openings are locatedcircumferentially about the bore but not diametrically opposite thesuction opening. In this embodiment the discharge is located at a rightangle to the suction opening and lends itself to installations requiringother than in-line piping. From a practical standpoint, this orientationis a limiting case as the discharge can be visualized as being radiallylocated anywhere between the showings of FIGURES 3 and 8. In thisalternate arrangement pistons 21, or 40 or 42 can be utilized.

It will accordingly be apparent that there is disclosed herein anarrangement of a pump wherein sealing of the piston to the wall of thebore in which it reciprocates is enhanced together with an arrangementof suction and discharge openings which result in simple installations.

I claim:

1. In a pump comprising a body having a bore therein, said bore having auniform diameter throughout its length, a suction opening along saidbore, a discharge opening along said bore, said suction and saiddischarge sesame openings being spaced circumferentially about the borewith the axes thereof in the same plane normal to the axis of said bore,a check valve positioned at said discharge opening, a piston of uniformdiameter fitted for reciprocation in said bore having a sealing surfaceto close the suction opening and a longitudinal recess in said piston,said recess opening through the wall of said piston and extending fromthe free end thereof toward the other end a distance sufiicient to be inalignment with the discharge opening throughout its reciprocation, thesurface area of said recess being greater than the cross sectional areaof the suction opening whereby fluid pressure upon said surface area ofsaid recess opposite the discharge Opening will exert a force in adirection normal to the axis of said piston and force the sealingsurface of said piston against the end of said suction opening totightly seal the same.

2. A pump as in claim 1 wherein said recess comprises a counterbore insaid piston and a longitudinal opening through the wall of the pistonfacing in the direction of the discharge opening.

References Qiterl in the tile of this patent UNITED STATES PATENTS2,685,987 Kaiser Aug. 10, 1954

